This invention relates to strutless synchronizers for manual transmissions and more particularly to a strutless/springless synchronizer that utilizes the inherent resilient properties of a composite blocking ring composed of fiber reinforced thermosetting resin formed with integral raised detent bumps.
The U.S. Pat. No. 4,776,228 issued Oct. 11, 1988 to Razzacki et al., and entitled Strutless Synchronizer discloses an improved synchronizer having an annular wire spring interposed between an internally splined sleeve, mounted for axial sliding movement on a transmission main shaft an associated metal blocking ring. Selected ones of the sleeve splines are formed at their extremities with radially inwardly extending "tall" cam-like teeth. Each tall tooth has a dual chamfered face portion arranged in opposed relation to the annular wire spring. The blocking ring has three equally spaced lugs each formed with a transverse groove sized to axially capture the wire spring so as to allow the spring freedom to rotate in its grooves relative to the blocking ring. Each time the sleeve is shifted toward meshed engagement with an associated main shaft ratio gear its detent teeth chamfered faces compress the wire spring at random points thereby minimizing spring wear while the grooves positively retain the spring also insuring instant unloading of the blocking ring.